iowatcher: Use queue events if issue not available

Currently queue depth and latency graphs are generated from ISSUE and
COMPLETE events. For traces which miss the ISSUE events (e.g. from
device mapper) use QUEUE events instead. The result won't be as great
but it still conveys some useful information.

Signed-off-by: Jan Kara <>
Signed-off-by: Jens Axboe <>
1 file changed